Abrading machine shoe construction



NOV. 25, 1952 PLANCON ETAL 2,618,913

ABRADING MACHINE SHOE CONSTRUCTION Filed Feb. 23, 1950 2 SX-IEETS-Sl-iEET 1 45 o o a o a a o 0 o C l7 E I I 4 I I 4 j I E- INVENTORS, v 6'60 6 If Fla/7C0 74a if -Zmfl 14 7? MFQZZ.

Mg v zauq G. H. PLANCON ETAL ABRADING MACHINE SHOE] CONSTRUCTION Nov. 25, 1952 2 SHEETSSI-IEET 2 I Filed Feb. 23. 1950 Patented Nov. 25, 1952 ABRADING MACHINE SHOE CONSTRUCTION George H. Plancon, Paul R. Baker, and Dana F. McFall, Detroit, Mich.

Application February 23, 1950, Serial No. 145,862 4 Claims. (01. 51-170) This invention relates generally to backing devices for yieldably engaging abrasive or polishing elements, and more particularly to a shoe mechanism for sanding machines, polishing machines, or the like.

In the past, many shoe mechanisms have been devised for engaging abrasive elements such as abrasive belts on sanding machines, in order to attempt to cause such abrasive elements to follow the contour of a workpiece. Some of these machines have been devised for use with abrasive elements in the sanding, grinding, or polishing at substantially flat surfaces, in order to attempt to cause the abrasive element to follow any minute undulations in the flat surface, so as to thereby finish the entire surface in a desired manner. Other shoes have been devised in an attempt to cause the abrasive element to properly follow irregular or curved contours of workpieces without destroying the preformed or desired contour of the workpieces. So far as is known, no one has heretofore devised a shoe mechanism which will properly maintain an abrasive element in engagement with a flat surface as well as a radiused or curved surface of a workpiece, so as to properly sand or polish such surfaces, without any danger of destroying the contour thereof. Furthermore, most shoes which have been heretofore devised frictionally engage the moving abrasive element and thus tend to create a large amount of heat, and also overwork the driving mechanism for the abrasive element. The applicants have overcome this latter difiiculty with the shoe mechanism of this invention and have at the same time provided a shoe mechanism which is equally. applicable for the sanding or polishing of flat surfaces, as well as complexly curved surfaces, irrespective of the contour thereof.

It is therefore an object of this invention to provide a shoe mechanism for use in conjunction with abrasive or polishing elements and operating devices therefor, which will not overload the element driving mechanism, due to frictional engagement with the element, and which will cause or allow the element to properly follow and engage any desired contour of a workpiece in the finishing of a workpiece surface.

It is a still further object of this invention to provide a shoe mechanism of the aforementioned type, which may be easily applied to various types of abrasive machines and is usable in conjunction with various types of abrasive elements.

It is a still further object of this invention to provide a shoe mechanism of the aforementioned type, including a plurality of members which yieldably engage the abrasive element and all of which exert the same pressure on the abrasive element at the same time, irrespective of the relative position of the engaging members relative to each other.

It is a still further object of this invention to provide a shoe mechanism of the aforementioned type, which is especially efficient in operation, simple in construction, inexpensive to manufacture and maintain, and compact in arrangement.

These and other objects of this invention will become more apparent from the following de taileddescription, taken in conjunction with the accompanying drawings, in which:

Figure l is a front elevational view of abelt sanding machine having .the shoe mechanism of this invention connected therewith, with parts broken away in section for purposes of clarity;

Fig. 2 is an enlarged fragmentary sectional view of the structure illustrated in Figure 1, taken along the line 2-2 thereof;

Fig. 3 is a fragmentary sectional view of the structure illustrated in Fig. 2, taken along the line 3-3 thereof;

Fig. 4 is a fragmentary end elevational View of the structure illustrated in Fig.1, engaging a workpiece of a particular contour; and

Fig. 5 is a fragmentary side elevational view of the structure illustrated in Fig. l, engaging a workpiece of a still different contour.

The shoe mechanism of this invention is usable in conjunction with various types of machines or devices for finishing workpieces, such polishers, sanders, or the like, and is usable in conjunction with different types of such devices, such as for example, belt sanders or disk sanders. For purposes of illustration, the shoe mechanism 8 is shown in conjunction with a portable belt sander which includes, as can be seen in Fig. l, a housing 9, having handles llconnected therewith, which may be grasped by an operator using the belt sander in order to lift and manipulate the same. A pair of spaced pulleys 13 are rotatably supported on the housing 9 by any suitable means, such as axles 15, which have their axes disposed in a common horizontal plane. A suitable abrasive sanding belt 11 extends around the pulleys I3 and is frictionally engaged thereby so that when the pulleys are rotated, the belt will be rotatably driven. The sanding machine herein illustrated is air operated and suitable fluid operated motors are disposed in the housing for driving the pulleys 13. An air hose -19 is connected with the housing 9 at 2| for supplying compressed air to the sander and an operating valve 22 is disposed adjacent the air inlet for starting and stopping the sanding machine motors.

The shoe mechanism 8 is illustrated as being disposed between the pulleys l3 and the upper and lower horizontal portions of the sanding belt l1. While the shoe mechanism 8 may be constructed in various ways, it is shown as including a stationary cylinder or chamber member 23 in the form ofa 'rectangular metal block. The member 23is provided with a plurality of transversely spaced rows of longitudinally spaced, vertically extending apertures or bores 21. The bores 27, in alternate rows, are longitudinally spaced or ofiset from the bores in adjacent rows, so that the bores are disposed in a staggered relationship. The upper portion of the block member 23 is provided with a plurality of transversely spaced, longitudinally extending, horizontal passageways 29, which are disposed between the adjacent rows of bores 21 and break into and communicate with the upper ends of the bores 21. The opposite ends of the passageways 29 are closed by any suitable means, such as plugs 3|. A domelike member 33 is connected to the top of the member 23 and communicates with the passageways 29 through suitable apertures35. One end of a fluid conduit 31 is connected to the member 33 at 39 so that fluid under pressure can flow into thepassageways 29 and the upper ends of all of the bores 21. A suitable relief valve 4! is supported on the member 23 and communicates with the passageways 29 through an aperture 43. The relief valve may be adjusted to control the maximum fluid pressure in the passageways 29 and bores 21. It will thus be seen that a plurality of air or fluid cylinders are provided which are interconnected by the horizontal passageways 29, or other suitable means, such as a cylinder head or'the like, which in turn are connected with a suit-able fluid inlet.

A bore-fitting rodlike member or piston 45 is slidably disposed in each of the bores 21 and has its lower end projecting below the member 23 and forked to rotatably support anti-friction rollers or bearings 41. Sui-table means are provided for limiting the extension movement of the pistons and in the embodiment illustrated each of the rodlike members 45 is provided with an axially elongated slot 49 therein. A transversely extending pin extends through the slots 49 of each group oftransversely aligned rods or pistons and is supported in the member 23 so as to limit the vertical movement of the rod members 45 in their respective bores 21. The flow of fluid or air under pressure into the passageways 29 and the upper ends of the bores 21 will normally move the rod members 45 to their downwardmost position, as determined by the pins 5 I. The stationary blocklike member 23 is connected with a stationary portion of the sanding machine by any suitable means, such as plate 53, and is 50 positioned that when the rod members 45 are in their downwardmost position, the bottoms of the rollers 41 will be disposed below the bottoms of the pulleys I3. It will thus be seen that the plurality of rollers 41 engage the lower portion of the sanding belt I! between the pulleys l3 to provide a workengaging area which is controlled by the shoe for sanding workpieces in a desired manner.

Due to the fact that fluid, under pressure, is contained in the stationary member 9, the same fluid pressure is acting on the upper end of each of the rod members 45, irrespective of the relative extended or retracted positions of the various rod members and their rollers. Therefore, the

shoe mechanism will retain the belt in engagement with any desired workpiece contour. For example, if it is desired to sand a tubular member 51, such as illustrated in Fig. 4, the operator merely places the lower portion of the sanding machine belt I! on the tubular member and exerts a pressure thereon. The rollers or bearings 41 which are engaging the belt will cause the belt to engage-the arcuate surface of tliettubular member 5! with the samepressure' ateve'ry point, due to the fact that even though the vertical positions of the rollers are varied, the same air pressure is acting against each rod member 45, so that there is no excessive pressure applied against the'rod members, which are retracted the greatest amount, due to the engagement with the workpiece contour. Thus, the construction of this invention insures that a greater pressure will not be applied to any one part of the arcuate surface of the tubular member 51, so as to destroy the contour thereof or remove more metal or material from any one portion than from another portion. x a

- The same is true in the sanding of the arcuate surface of a roller or drumlike member 59, as lustrated in Fig. 5, wherein it will be seen that the rod members 45 and rollers-41 will assume various retracted and extending positions the maintenance of the belt .in engagement with the arcuate surf-ace of the roller or drummember, without exerting any greater pressure at anyone point along the arcuate surface than at any other point. The belt l'l. may thus be'presente'd'at any angle to the workpiece in accordance-with-- the contour of the workpiece and the best method of sanding the surface thereof, "and the shoe mechanism will cause the proper engagement .of the sanding belt with the workpiece contour. As" a large number of rollers 4! are provided, which are disposed in an offset or staggered relation, the rollers in effect provide a continuous'surface or area applying pressure to the belt. Practically any contour, whether it be a small radius, large radius, complex or reverse curve, -etc., may be sanded accurately with :a sanding machine employing the shoe mechanism of this invention.

If it is desired to sand a flat surface, the re= pulleys I3, the portions of the belt adjacent the.

pulleys I 3 will not engage the flat surface, but only the portions of the belt engaged by the shoe rollers 41. When the operator applies the dOWl'lra ward pressure on the handles II, the rod members 45 will be partially retracted so that if there are any undulations in the flat surface, the rollers will move independently upwardly or downwardly to cause the belt to follow such undulations and completely finish the flat surface in,

the desired manner. When the device is being used to sand tapered surfaces, compound radi-- uses or other curved or complex contours, the relief valve 4| is generally adjusted so that relatively light fluid pressure is exerted on the rod members 45 and rollers 41. Thus, the device may be moved along the contoured surface and the rollers 41 will move inwardly or outwardly to cause the belt to follow and engage the surface, and the machine can be used to sand any surfacemerely by mov ng the machine-and belt along thecontour of the workpiece and if desired or necessary, rocking the machine relative to the workpiece. It is important to realize that with the shoe of this invention, equal pressure is applied to the belt and workpiece throughout the extent of the shoe so that there is no increased pressure on the opposite ends of the belt, as is prevalent with so many of the shoes now in use.

Furthermore, with this shoe mechanism, in the sanding of all contours, the belt moves away from either end of the shoe parallel with the pulleys 13, so that any tendency for the belt to feed transversely off the pulleys and possibly become disengaged therefrom, is eliminated. As the rollers 41 and rod members 45 are all identical in construction, they are interchangeable, so that if the shoe is being used continuously to sand any particular contour which may tend to cause more wear on certain of the rollers than on others, the rollers may be easily interchanged so that the shoe will have an extremely long life.

It will thus be seen that the shoe mechanism of this invention may be used in conjunction with various types of abrasive polishing or work engaging elements and machines and will exert yieldable pressure against the element, which pressure will be equal throughout the extent of the shoe and irrespective of the position of the belt-engaging elements or rollers, so that both fiat surfaces and other contours of a workpiece may be accurately and easily sanded in a manner which has not been heretofore possible. It will also be appreciated that the shoe mechanism of this invention is extremely simple and efficient in operation, relatively inexpensive to manufacture and maintain, and may be easily connected with various types of devices to permit the performance of various operations in accurate manner not heretofore possible.

What is claimed is:

1. A belt sanding machine including a pair of spaced pulley elements, means rotatably supporting said pulley elements on axes disposed in the same horizontal plane, means for rotatably driving said pulley elements, an abrasive belt extending around said pulleys and adapted to be rotatably driven therewith, a shoe mechanism including a plurality of anti-friction elements engaging said belt between said rollers, a member supported on said machine above the lower portion of said belt between said pulleys, said member having a plurality of vertically extending bores therein, bore-fitting members slidably mounted in said bores and connected with said anti-friction elements, means interconnecting said bores and adapted to have fluid under pressure conveyed thereto for exerting the same fluid pressure on the upper ends of all of said borefltting members, whereby to yieldably resist upward movement of said anti-friction elements and bore-fitting members.

2. A belt sanding machine including a pair of spaced pulley elements, means rotatably supporting said pulley elements on axes disposed in the same horizontal plane, means for rotatably driving said pulleys, an abrasive belt extending around said pulleys and adapted to be rotatably driven therewith, a shoe mechanism including a plurality of spaced anti-frictionelements engaging said belt between said pulleys, a member supported on said machine above the lower portion of said belt between said rollers, said member having a plurality of vertically extending bores therein, bore-fitting members slidably mounted 6 in said bores and connected with said anti-friction elements, means interconnecting said bores and adapted to have fluid under pressure conveyed thereto for exerting the same fluid pressure on the upper ends of all of said bore-fitting members, whereby to resist upward movement of said anti-friction elements and bore-fitting members, said anti-friction elements being normally disposed in a plane below the bottoms of said pulley elements.

3. A belt sanding machine including a pair of spaced pulley elements, means rotatably supporting said pulley elements on axes disposed in the same horizontal plane, means for rotatably driving said pulley elements, an abrasive belt extending around said pulley elements and adapted to be rotatably driven therewith, a block member supported on said machine above the lower portion of said belt between said pulleys, said member having a multiplicity of vertically extending bores therein, bore fitting members slidably mounted in said bores and connected with a multiplicity of antifriction elements which in turn engage said belt between said pulleys, said antifriction elements being so closely spaced that their total projected areas are substantially equal to the projected area of the block member, means interconnecting said bores and adapted to have fluid under pressure conveyed thereto for exerting the same fluid pressure on the upper ends of all said bore fitting members whereby to yieldably resist upward movement of said antifriction elements and bore fitting members.

4. A belt sanding machine including a pair of spaced pulley elements, means rotatably supporting said pulley elements on axes disposed on the same horizontal plane, means for rotatably driving said pulley elements, an abrasive belt extending around said pulleys adapted to be rotatably driven therewith, a shoe mechanism mcluding a multiplicity of rotatable antifriction elements positioned in staggered lateral and longitudinal rows so as to produce an overlapping of the exterior peripheral portions of said elements, a block member supported on said machine above the lower portion of said belt between said pulleys, said member having a multiplicity of vertically extending bores therein, bore fitting members slidably mounted in said bores and connected with said antifriction elements, means interconnecting said bores and adapted to have fluid under pressure conveyed thereto and exert the same fluid pressure on the upper ends of all of said bore fitting members whereby to yieldably resist upward movement of said antifriction elements and bore fitting members, said antifrlction elements engaging said belt between said pulleys so as to yieldably back said belt over a substantially continuous area defined by the outer rows of said elements.

GEORGE H. PLANCON. PAUL R. BAKER. DANA F. MCFALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 818,518 Clemons Apr. 24, 1906 1,181,330 Mattison May 2, 1916 1,480,285 Moore Jan. 8, 1924 2,213,992 Morse Sept. 10, 1940 

